"""Voice Activity Detection (VAD) utilities for VoIdeaAI.

Server-side VAD analysis and parameter processing.
Actual VAD is performed client-side via Web Audio API (getUserMedia).
"""

VAD_DEFAULTS = {
    "enabled": True,
    "noise_threshold": 0.3,
    "silence_timeout_ms": 1500,
    "min_audio_duration_ms": 300,
}


def validate_vad_params(params: dict | None = None) -> dict:
    """Validate and return VAD parameters with defaults."""
    if not params:
        return dict(VAD_DEFAULTS)
    result = dict(VAD_DEFAULTS)
    if isinstance(params.get("noise_threshold"), (int, float)):
        result["noise_threshold"] = max(0.0, min(1.0, float(params["noise_threshold"])))
    if isinstance(params.get("silence_timeout_ms"), (int, float)):
        result["silence_timeout_ms"] = max(100, int(params["silence_timeout_ms"]))
    if isinstance(params.get("min_audio_duration_ms"), (int, float)):
        result["min_audio_duration_ms"] = max(50, int(params["min_audio_duration_ms"]))
    if isinstance(params.get("enabled"), bool):
        result["enabled"] = params["enabled"]
    return result


def should_process_audio(
    duration_ms: int | None = None,
    vad_params: dict | None = None,
) -> tuple[bool, str | None]:
    """Check if audio should be processed based on VAD parameters.

    Returns (should_process, reason_if_skipped).
    """
    params = validate_vad_params(vad_params)
    if not params["enabled"]:
        return True, None
    if duration_ms is not None and duration_ms < params["min_audio_duration_ms"]:
        return False, f"Audio too short: {duration_ms}ms < {params['min_audio_duration_ms']}ms"
    return True, None